It is proposed to study, in a quantitative manner, the effects of certain allosteric effectors on one of the enzymes most critically concerned with the metabolic control of glycolysis, pyruvate kinase. The method of choice is direct optical scanning gel chromatography developed by Brumbaugh and Ackers (J. Biol. Chem. 243:6315 (1968). Huge amounts of data can be collected quickly and processed statistically to provide information concerning changes in conformation, stoichiometries of association (dissociation) and their related equilibrium constants, and the stoichiometries and binding constants of the effector ligands. In particular, the role of fructose-1,6-diphosphate in the activation and stabilization of pyruvate kinase will be studied along with the determination of the mode of enzymatic inactivation created by dilution and/or low temperature.